How to Convert double to int in Java?

In this tutorial, you will learn how to convert a double value to an int in Java. We’ll explore explicit casting, how to handle the decimal part, and provide examples to demonstrate the conversion process.

Java – Convert double to int

Converting double to int in Java – In Java, converting a double to an int requires explicit casting because double is a floating-point type while int is an integer type. This conversion will truncate the decimal part of the double value, returning only the whole number part.

Explicit Conversion from double to int

To convert a double to an int in Java, you need to use an explicit cast. This conversion will drop the decimal part, keeping only the integer portion of the number.

Example of Explicit Conversion

public class DoubleToIntExample {

    public static void main(String[] args) {
        double doubleVal = 9.99;
        int intVal = (int) doubleVal; // Explicit conversion from double to int
        System.out.println("Double value: " + doubleVal);
        System.out.println("Int value after conversion: " + intVal);
    }
}

Output

Double value: 9.99
Int value after conversion: 9

In this example, the double value 9.99 is explicitly cast to an int, resulting in 9 as the decimal portion is truncated.

Rounding Before Conversion

If you want to round the double value to the nearest integer before converting it to an int, you can use Math.round(). This method rounds the double value to the nearest whole number and returns a long, which can then be cast to an int.

Example of Rounding Before Conversion

public class DoubleToIntExample {

    public static void main(String[] args) {
        double doubleVal = 9.99;
        int intVal = (int) Math.round(doubleVal); // Rounding and converting to int
        System.out.println("Double value: " + doubleVal);
        System.out.println("Int value after rounding: " + intVal);
    }
}

Output

Double value: 9.99
Int value after rounding: 10

In this example, Math.round() rounds 9.99 up to 10 before converting it to an int.

Conclusion

Converting a double to an int in Java requires explicit casting, which truncates the decimal part. If rounding is desired, use Math.round() to achieve the nearest whole number before converting. Be cautious, as any decimal part will be removed in the conversion.